<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <script src="../vue.js"></script>
  </head>

  <body>
    <div id="app">
      <h1>{{isHot?"热啊":"冻啊"}}</h1>
      <button @click="isHot = !isHot">change</button>
    </div>
    <script>
      Vue.config.productionTip = false;

      const vm = new Vue({
        el: "#app",
        data() {
          return {
            isHot: true,
          };
        },
        watch: {
          //如果没有深度监听和立即监听,可以直接使用watch的简写
          isHot() {
            console.log("改变天气了");
          },
        },
      });
    </script>
  </body>
</html>
